Intuition leads to the flat Earth society and bloodletting;
experiments lead men to the moon and microsurgery.
- Seth Mnookin
 Up through the 20th century, one of the most
serious diseases of mankind was smallpox.
 One of out every 10 children born in France and
Sweden died of smallpox.
 The only known “cure” was to contract the disease
and recover.
 Some inoculated themselves
with fluid and pus from the sick,
hoping to contract a mild case
and survive.
 A British physician named
Edward Jenner observed that
dairymaids living in his
hometown often contracted
cowpox, a nonlethal disease
with similar symptoms to
smallpox.
 He decided to intentionally
infect a young boy with
cowpox, then expose him to
smallpox.
 Immunity was successfully
Edward Jenner vaccinating a child with
cowpox from a dairymaid. Source:
Bettman Archive / Corbis.
conferred to the boy.
3
 A different virus was eventually
discovered for use in smallpox
vaccinations.
 Produced much milder
symptoms.
 Smallpox was declared
eradicated by the World
Health Organization in 1980.
 The same basic technique has
been used to develop vaccines
for other illnesses, such as
measles, tetanus, chickenpox,
whooping cough, and others.
A monument dedicated to smallpox
eradication at the WHO headquarters
in Geneva. Source: Wikimedia.
4
 Science assumes that everything in the universe can be
explained, given enough data and experimentation.
 All ideas in science are constantly being tested,
evaluated, and re-considered.
 Hypothesis: Testable prediction based on prior
knowledge and observation.
 Can be supported or rejected based on an
experiment.
 Theory: Broad explanation based on many experiments
and high amounts of data.
 Examples: Evolution, Plate Tectonics, Big Bang
 Discoveries must be reproducible -- designed and
recorded such that the results can be repeated by other
researchers.
5
 A far different idea is pseudoscience, which appears or
claims to be science, but does not follow scientific
principles.
6
 The theory that life arose spontaneously from non-
living matter persisted from ancient times through the
19th century.
 One recipe for life called for dirty garments and husks
of wheat to be added to a jar.
 Wait 21 days, and mice appear!
 This belief was based in false
science.
 Could it be replicated
consistently?
 Were any other possible
explanations tested?
7
 The primary goal of alchemists
during the middle ages was to
discover a way to transform materials
of little value (such as lead) to gold.
 A chemist named Hennig Brand in
1669 was studying urine, observing
that it had a color similar to gold.
 He accidentally discovered
phosphorus; an element that glowed.
 Hennig, like other alchemists, kept his
discoveries secret. The study of
chemistry advanced little during this
time.
The Alchemist in
Search of the
Philosophers Stone
(1771) by Joseph
Wright.
8
Source: The Eyes of Nye - Pseudoscience. Dir. Steve Wilson. Perf. Bill Nye. Disney
Educational Productions, 2005. DVD.
 A “new” zodiac chart
was created by the
Minnesota
Planetarium Society to
reflect the change in
the Earth’s rotation.
10
 All scientific
studies, regardless
of complexity,
follow the same
series of steps,
called the scientific
method.
11
 The first step is making an observation.
 Information gathered by noticing specific details of a
phenomenon.
 Dr. Edward Jenner observed that dairymaids who
contracted cowpox seemed to be protected from the
more deadly smallpox.
The Dairy Maid,
1650s, by Aelbert
Cuyp.
12
 The goal is to be able to explain the observation.
 A hypothesis, or testable explanation, will be made
based on the scientist’s prior experience and research.
 Hypotheses are preliminary explanations – they can and
are often proven false.
 Dr. Jenner’s hypothesis was that exposure to cowpox
would grant immunity to smallpox.
 The hypothesis must be tested.
13
 The experiment tests the hypothesis under controlled
conditions.
 A controlled experiment attempts to test a single variable,
while keeping all others constant.
 The experimental group receives the variable, while the
control group does not.
 Dr. Jenner’s experiment was to inoculate the 8 year-old son
of his gardener with fluid from a cowpox pustule, allow the
infection to pass, then repeat with a smallpox pustule.
 The boy (experimental group) survived 20 inoculations
without succumbing to smallpox!
 The conclusion states whether or not the hypothesis is
supported by the results of the experiment.
14
 The final step is communication, where the results are
published and reviewed by others to check for errors,
bias, or other issues.
 Dr. Jenner submitted his study to the Royal Society for
Medicine, but was told he needed more proof.
“The Cow-Pock—or—
the Wonderful Effects
of the New
Inoculation!—vide. the
Publications of ye
Anti-Vaccine Society.”
- Satirical cartoon,
1802.
15
 Accounting for every single variable in a scientific study is
nearly impossible. There are many factors that can cause
error.
 There is where probability comes in. This is the likeliness
that a result occurred simply due to random chance.
 This can be countered by increasing sample size, or the
number of observations used in an experiment or study.
 Dr. Jenner was able to locate several other parents who
were willing to volunteer their children. He even
included his own 11 month-old son in the study.
 The results were finally published. Jenner called his
technique vaccination after the Latin word for cow
“vacca”.
16
 Controlled experiments aren’t always possible or ideal.
 Natural experiments are conducted in the field under
normal circumstances.
 The advantage is that these experiments take place in a
more accurate, realistic environment.
 The disadvantage is that natural phenomena are often
very difficult to find.
 Another significant problem in science is bias; the
preference for an experiment to turn out in a certain
way.
 Bias is not always intentional, but must be controlled
by the experimental design.
 A blind experiment is conducted so the experimental
subjects do not know which is the control and which is
the experimental group.
 Eliminates the “placebo effect”
 A double-blind experiment also prevents the actual
scientists from knowing which is the control or
experimental group.
18
“Charged Water Experiment”
PBS NOVA, Secrets of the Psychics, Original airdate: March 28, 2000.
“The Medical Psychic”
PBS NOVA, Secrets of the Psychics, Original airdate: March 28, 2000.
 There are many examples of published studies or report
that have been later found biased, flawed, or outright
fraudulent.
 These are always detected, eventually, due to the scientific
method and peer review.
 The net effect is loss of time, resources, and public mistrust.
 In 1998, Dr. Andrew Wakefield published a study in the
British journal The Lancet documenting a link between the
MMR vaccine and autism in children.
 In the following year, over a thousand articles were written
about the possible link, very few by actual experts in the field.
 Vaccine rates dropped from 92% to 85% in the U.K., with
similar results in other countries.
21
 Wakefield’s conclusions were
found out to be fraudulent
and that he had manipulated
the data.
 Several outbreaks of measles
and mumps occurred across
the world from 2002-2008.
 The United States has seen a
similar effect, with
vaccination rates below CDC
recommendations in several
schools.
According to a Time
Magazine survey, 24% of
adults place “some trust” in
celebrities’ opinions on
vaccines.
22